Safety trocar penetrating instrument with safety shield having resilient legs

ABSTRACT

A safety trocar penetrating instrument particularly useful in least invasive surgery includes a portal sleeve, a trocar disposed in the portal sleeve and having a sharp, solid, angled tissue penetrating distal end and a safety shield disposed in the portal sleeve and receiving the trocar, the safety shield being movable relative to the trocar between an extended position wherein a distal end of the safety shield protects the sharp tip and a retracted position exposing the sharp tip. The configuration of the distal ends of the trocar and the safety shield in the retracted position present a substantially continuous, angled surface for penetrating tissue. A hub receiving proximal ends of the trocar and safety shield includes a locking mechanism allowing the safety shield to be automatically or optionally locked in the extended position and permitting selective, releasable or automatic locking of the safety shield in the retracted position.

This application is a division of patent application Ser. No.08/313,655, filed Sep. 26, 1994 now U.S. Pat. No. 5,591,190 which was acontinuation of Ser. No. 07/817,113, filed Jan. 6, 1992, now U.S. Pat.No. 5,350,393.

BACKGROUND OF THE INVENTION

1. Field Invention

The present invention pertains to surgical penetrating instruments foraccessing cavities within the body and, more particularly, to suchpenetrating instruments formed of trocars having solid, tissuepenetrating, sharp tips and safety shields surrounding the trocars forpreventing tissue from contacting the sharp tips after entry into bodycavities.

2. Discussion of the Prior Art

Trocars are commonly used for accessing cavities within the body andestablishing an endoscopic portal for various procedures to be performedby least invasive surgery. Portal sleeves or cannulas are normallydisposed around the trocars to be positioned upon penetration into thecavity by the trocar. Trocars include a sharp tissue penetratingpyramidal distal end or tip to pierce or penetrate tissue forming thecavity wall, and the force required to penetrate the cavity wall isdependent upon the type and thickness of the tissue of the wall. Oncethe wall is penetrated, it is desirable to prevent the sharp tip of thetrocar from inadvertently contacting tissue in or forming the cavity,and a particular problem exists where substantial force is required topenetrate the cavity wall in that, once penetration is achieved, thelack of tissue resistance can result in the sharp trocar tip travelingtoo far into the cavity and injuring adjacent tissue. Safety trocarshaving a spring-biased protective shield disposed between an outerportal sleeve and an inner trocar are marketed by Ethicon, Inc. as theEndopath and by United States Surgical Corporation as the Surgiport, andU.S. Pat. No. 4,535,773 to Yoon, U.S. Pat. No. 4,601,710 to Moll andU.S. Pat. No. 4,654,030 to Moll et al are exemplary of such safetytrocars.

A disadvantage of prior art safety trocars is that the safety shieldscannot be optionally locked in an extended position protecting the sharptrocar tips for safety in handling and use. A further disadvantage ofprior art safety trocars is that the safety shields cannot beselectively retracted to expose the sharp trocar tips without a forcebeing applied to the safety shields with tissue contact. Accordingly,the sharp trocar tips in prior art safety trocars cannot be effectivelyused in further penetration or treatment of tissue after a cavity wallis initially penetrated; and, therefore, the types of surgicalprocedures that can be performed with prior art safety trocars arethusly limited. Another disadvantage of prior art safety trocars is thatthe protective shields form an irregular surface or profile with thetrocars resulting in increased resistance from tissue during penetrationof a cavity wall, greater trauma and damage to tissue and possiblejamming and trapping of tissue between the trocars and the safetyshields.

SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to overcomethe above-mentioned disadvantages of prior art safety trocars.

Another object of the present invention is to optionally allow lockingof a safety shield in an extended position from a solid, sharp distalend of a trocar of a safety trocar penetrating instrument.

The present invention has a further object in that a safety shieldmovable relative to a trocar within a portal sleeve is biased toward anextended position and can be selectively, releasably, locked in aretracted position exposing a solid, sharp, distal end of the trocarprior to or after penetration of a cavity wall.

Additionally, it is an object of the present invention to provide asafety trocar penetrating instrument having a safety shield movablebetween an extended position protecting a solid, sharp distal end of atrocar and a retracted position exposing the sharp distal end, thesafety shield being distally biased toward the extended position andwherein the safety shield can be optionally automatically locked in theextended position when returned to the extended position by the distalbias.

Yet another object of the present invention is to construct a safetytrocar penetrating instrument such that a distally biased safety shieldcan be manually pulled proximally toward a retracted position to exposea solid, sharp distal end of a trocar without requiring a force appliedto the safety shield from tissue contact.

A further object of the present invention is use of a pin and slotmechanism to provide selective locking of a safety shield distallybiased relative to a trocar, the pin extending externally of a housingto form a handle graspable by a surgeon to selectively move the safetyshield between extended and retracted positions when the pin is movedalong a longitudinal portion of the slot and to releasably lock thesafety shield in the extended or retracted position when the pin ispositioned in transverse portions of the slot.

A still further object of the present invention is to provide a safetytrocar penetrating instrument having a trocar received in a safetyshield movable relative to the trocar and disposed in a portal sleevehaving an end secured in a housing, the safety shield and trocarextending through an opening in the housing and wherein adapter plugscan be positioned in the opening to form a seal with instruments ofvarious sizes inserted therethrough when the safety shield and trocarare withdrawn from the portal sleeve.

Another object of the present invention is to provide a trocar, a safetyshield receiving the trocar and movable relative to the trocar betweenextended and retracted positions and a portal sleeve mounting the safetyshield wherein the trocar, the safety shield and the portal sleeve forma smooth profile in the retracted position to facilitate insertion intissue forming a cavity wall.

An additional object of the present invention is to provide a safetytrocar penetrating instrument having a trocar and a safety shieldmovable relative to the trocar between extended and retracted positionsand wherein distal ends of the trocar and safety shield are configuredin the retracted position to permit penetration of tissue of a cavitywall with a rotational motion providing relatively slower insertion withrelatively greater control of the depth of insertion of the distal endsin tissue of the cavity wall.

Yet another object of the present invention is to control locking of asafety shield relative to a trocar in response to hand squeezingpressure of an end cap relative to the hub of a safety trocarpenetrating instrument.

Some of the advantages of the present invention are that anatomicalcavities of various sizes can be safety penetrated with a trocar toestablish a portal in communication therewith, safety in handling anduse of a safety trocar penetrating instrument is enhanced, penetrationinto additional tissue, such as into a cystic cavity or soft organstructure (e.g. ovarian cyst penetration or liver tissue biopsy), afterpenetration of a cavity wall can be accomplished with a singleinstrument, the types of surgical procedures utilizing a trocar can beexpanded, safety trocar penetrating instruments can feasibly be employedin thoracic and cranial surgery, second puncture endoscopic or leastinvasive procedures are facilitated, exposure of medical personnel toinadvertent contact with the sharp tip of the trocar is minimized, asingle puncture can be used for both insufflation and forming anendoscopic portal thereby simplifying procedures such as laparoscopy,trauma and damage to tissue is minimized, tissue jamming and trapping isavoided and safety trocar penetrating instruments according to thepresent invention can be inexpensively manufactured to be reusable ordisposable.

The present invention is generally characterized in a safety trocarpenetrating instrument including a trocar having a solid, sharp distalend or tip, a safety shield disposed concentrically around the trocarand movable relative to the trocar between an extended positionprotecting the sharp trocar tip and a retracted position exposing thesharp trocar tip, a hub receiving proximal ends of the trocar and safetyshield and a portal sleeve receiving the safety shield to establishcommunication with an anatomical cavity upon penetration of the cavityby the trocar. The safety shield is distally biased toward the extendedposition, and a locking mechanism automatically locks the safety shieldin the extended position after the safety shield is returned thereto bythe distal bias after penetration of tissue forming the cavity wall orcan optionally allow locking of the safety shield in the extendedposition with the safety shield being free to move toward the retractedposition when the safety shield is not optionally locked in the extendedposition. The locking mechanism also provides selective, releasable,locking of the safety shield in the retracted position or can allowautomatic locking of the safety shield in the retracted position. Ahousing securing a proximal end of the portal sleeve has an opening forpassage of the safety shield and trocar therethrough and into the portalsleeve. The safety shield and trocar can be withdrawn from the portalsleeve, and adapter plugs can be positioned in the opening to form aseal with instruments of various sizes inserted therethrough. Variousconfigurations for the distal ends of the trocar and the safety shieldprovide a smooth profile with the portal sleeve in the retractedposition to facilitate penetration of tissue forming the cavity wall.

Other objects and advantages of the present invention will becomeapparent from the following description of the preferred embodimentstaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a broken side view, partly in section, of a safety trocarpenetrating instrument according to the present invention.

FIG. 2 is a broken section of the hub and locking mechanism of thesafety trocar penetrating instrument of FIG. 1.

FIG. 3 is a broken perspective view, partly in section, of an adapterplug for the safety trocar penetrating instrument of FIG. 1.

FIG. 4 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 1 with the safety shield inan extended position prior to penetrating tissue.

FIG. 5 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 1 with the safety shield ina retracted position during penetration of tissue.

FIG. 6 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 1 with the safety shield inan extended position after penetration of tissue.

FIG. 7 is a broken view, partly in section, of a modification of thedistal end of a safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 8 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 7 with the safety shield inthe retracted position.

FIG. 9 is a broken view, partly in section, of a modification of adistal end of the safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 10 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 9 with the safety shield inthe retracted position.

FIG. 11 is a section taken along line 11--11 of FIG. 9.

FIG. 12 is a section taken along line 12--12 of FIG. 9.

FIG. 13 is a broken view, partly in section, of a modification of thedistal end of a safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 14 is a broken view, partly in section, of the distal end of asafety trocar penetrating instrument according to the present inventionwith the safety shield in the retracted position.

FIG. 15 is a broken view, partly in section, of a modification of thedistal end of a safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 16 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 15 with the safety shieldin the retracted position.

FIG. 17 is a broken view, partly in section, of a modification of thedistal end of a safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 18 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 17 with the safety shieldin the retracted position.

FIG. 19 is a broken view, partly in section, of a modification of thedistal end of a safety trocar penetrating instrument according to thepresent invention with the safety shield in the extended position.

FIG. 20 is a broken view, partly in section, of the distal end of thesafety trocar penetrating instrument of FIG. 19 with the safety shieldin the retracted position.

FIG. 21 is a perspective view of a locking spring for the safety trocarpenetrating instrument of the present invention.

FIG. 22 is a broken view, partly in section, of a modification of thehub and locking mechanism of the safety trocar penetrating instrument ofthe present invention.

FIGS. 23, 24, 25 and 26 are broken views, partly in section,illustrating stages of operation of the hub and locking mechanism ofFIG. 22.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A safety trocar penetrating instrument 30 according to the presentinvention is illustrated in FIG. 1 and includes an elongate trocar 32, asafety shield 34 movably disposed concentrically around trocar 32, anelongate portal sleeve 36 concentrically disposed around safety shield34, a hub 38 mounting trocar 32 and safety shield 34 and a housing 40mounting portal sleeve 36. The hub 38 can be latched to housing 40 withthe use of any suitable releasable mechanism, such as ball detents 42,allowing the hub to be removed from the housing withdrawing the trocarand safety shield from the portal sleeve. Accordingly, the safety trocarpenetrating instrument 30 can be considered to be formed of a portalunit and a trocar unit, the portal unit including portal sleeve 36 andhousing 40 and the trocar unit including trocar 32, safety shield 34 andhub 38.

Trocar 32 is preferably made of stainless steel with a cylindrical bodyhaving a diameter dependent upon the surgical procedure to be performedand the anatomical cavity to be penetrated. The trocar has a soliddistal end 44 terminating at a sharp tip 46 for penetrating anatomicaltissue. The distal end 44 can have various configurations; and, as shownin FIG. 1, the distal end 44 of the trocar has a pyramidal shape withthree, equally spaced facets terminating proximally at a cylindricalneck 48 which, in turn, terminates proximally at a frusto-conicalshoulder 50. A cylindrical body 52 extends proximally from shoulder 50and terminates at a proximal end 54 secured to an end wall 56 of hub 38by any suitable means, such as cement or threads. While the distal endof the trocar 32 is solid, the cylindrical body 52 can be either solidor tubular dependent upon manufacturing techniques utilized.

Hub 38 is preferably made of plastic to reduce cost and has an externalconfiguration to cooperate with housing 40 to be easily grasped with onehand for use in penetrating tissue. Hub 38 is substantially rectangularin cross-section and includes, as best shown in FIGS. 1 and 2, four sidewalls extending from a front wall 58 to end wall 56 to provide arearwardly flared outer profile with one side wall, indicated at 60,having a slot 62 therein.

Safety shield 34 is preferably made from a cylindrical length of a rigidor flexible material, such as stainless steel or plastic dependent uponuse of the safety trocar penetrating instrument, and has a blunt distalend 64 with a configuration to extend beyond and protect sharp tip 46 oftrocar 32 in an extended position. As best shown in FIG. 2, the safetyshield 34 has a cylindrical tubular body 66 extending along thecylindrical body 52 of trocar 32 and through an opening 68 in front wall58 of hub 38. Tubular body 66 terminates at a proximal end 70 disposedwithin the hub and carrying spaced annular ribs 72 and 74 between whichis rotatably mounted an annular member or plate 76 having a pin 78threadedly secured thereto and extending through slot 62, the pin 78having a spherical end or knob to be easily grasped. A helical spring 80is mounted in compression between plate 76 and end wall 56 of hub 38,and the spring 80 has longitudinally extending ends 82 received inapertures in plate 76 and end wall 56, respectively, such that thespring can be wound in torsion to bias the plate and the pin 78 carriedthereby in a clockwise direction looking from the proximal end of thesafety trocar penetrating instrument or upwardly looking at FIG. 1. Thehub 38 can be formed in any suitable manner to facilitate winding ofspring 80, such as molding the hub in parts or providing a rotatableinsert for receiving a proximal, longitudinally extending end 82 ofspring 80. The slot 62 formed in hub 38 has a longitudinal portion 84aligned in parallel relation with a longitudinal axis of the trocar 32,a distal transverse portion 86 and a proximal transverse portion 88having a recess 90 at the end thereof extending parallel with thelongitudinal slot portion 84. If desired, for purposes to be explainedhereinafter, the proximal transverse slot portion can extend in the samedirection as the distal transverse slot portion as shown in dashed linesat 92.

Portal sleeve 36 is preferably made of a cylindrical length of stainlesssteel or other suitable, medically acceptable, plastic or metal materialand can be rigid or flexible and transparent or opaque. The portalsleeve has a distal end 94 tapering to terminate at a peripheral edge 96disposed in substantial alignment with a proximal edge of conicalshoulder 50 such that the distal ends of the portal sleeve, the safetyshield and the trocar present a substantially smooth profile tofacilitate tissue penetration as shown in FIG. 5. The portal sleeve 36has a threaded proximal end 98 removably received in an internallythreaded nipple 100 extending from a front wall 102 of housing 40.Housing 40 is preferably made of plastic to reduce cost and has arectangular configuration in cross-section corresponding to thecross-sectional configuration of hub 38 with a flared external profileadjacent front wall 102 to facilitate grasping during use. Recesses 104and 106 are formed on opposite sides of nipple 100 and have a size andconfiguration to receive ball-type stopcocks 108 and 110, respectively,in a position such that the stopcocks are protected from inadvertentcontact which could cause breakage or malfunction. A valve assembly 112is mounted in housing 40 to control flow through the portal sleeve oncethe trocar unit is removed therefrom. The valve assembly can have anyacceptable configuration and, as shown, includes a flange 114 having anannular configuration with a threaded periphery to be threadedly securedin housing 40, a plurality of spaced, spreadable legs 116 extendingdistally from flange 114 to produce a normally conical configurationtapering to an apex as illustrated in dashed lines in FIG. 1 and aconical, stretchable sleeve or membrane 118, preferably made of arubber-like material such as silicone, having a configuration to tightlyfit over legs 116 such that the sleeve and legs are normally biased tothe closed position at the apex to prevent passage of fluids through thevalve assembly. The legs 116 and flange 114 are preferably integrallymade of unitary construction of a material, such as a plastic-likenylon, facilitating movement of medical instruments therethrough andallowing legs 116 to flex. The legs 116 are concentrically disposedaround a central opening 120 in flange 114 and are slightly spaced fromeach other by gaps which terminate at curved relief recesses.

A cylindrical tube 122 is secured in the central opening 120 throughflange 114, and a distal end of the cylindrical tube 122 engages aproximal annular portion of the valve assembly 112 at proximal ends ofthe legs 116. An adapter plug 124, as best shown in FIG. 3, is mountedon a proximal end of tube 122 and is integrally constructed of aflexible resilient material, such as Teflon, silicone rubber or plastic.The adapter plug 124 has a thick flange portion 126 with an annularrecess 128 therein for receiving the proximal end of tube 122 and acylindrical inner wall 130 extending from an inner edge of a centralaperture 132 in the flange 126 to be snugly received within tube 122.The thickness of wall 130 is dependent upon the size of the instrumentto be inserted through the portal sleeve 36 such that, if instrumentssmaller than the trocar unit are to be introduced into the body afterthe trocar unit is withdrawn from the portal sleeve, the adapter plug124 is removed from the proximal end of tube 122 and another adapterplug is inserted therefor having an inner cylindrical wall of greaterthickness to engage the smaller diameter instruments along the length ofthe inner cylindrical wall as shown in dashed lines at 134 in FIG. 3.That is, the thickness of the inner wall 130 and the diameter of thetubular passage defined thereby will vary dependent upon the diameter ofinstruments passed through the portal unit, and the diameter of thetubular passage will be substantially the same as or slightly less thanthe outer diameter of an instrument passed therethrough to produce aseal therearound extending along the length of the inner wall. Byutilizing various size adapter plugs with inner sealing walls toaccommodate various size instruments, an effective seal can be producedfor instruments varying greatly in size, for example from 2 mm to 12 mm.

In order to assemble the safety trocar penetrating instrument 30 asgenerally described above, the proximal end 70 of the safety shield 34,the spring 80 and the pin 78 are assembled within hub 38 with the spring80 torsionally wound to bias plate 76 upwardly looking at FIG. 1 aspreviously described. It will be appreciated that plate 76 is rotatablein the annular groove between ribs 72 and 74 such that rotation of plate76 does not cause rotation of the safety shield thereby assuring angularalignment of the distal ends of the trocar and the safety shield. Thepin 78 will be, accordingly, biased distally along longitudinal slotportion 84 to a position adjacent distal transverse slot portion 86 andwill be biased into distal transverse slot portion 86 due to thetorsional bias from spring 80 to releasably lock the safety shield inthe extended position. The trocar Unit formed by the trocar 32, thesafety shield 34 and the hub 38 is then combined with the portal unit bypassing trocar 32 and safety shield 34 through the central aperture 132in adapter plug 124 and through housing 40 and portal sleeve 36simultaneously spreading legs 116 of valve assembly 112 to produce asecond seal along the safety trocar penetrating instrument. That is, theconical sleeve 118 acts as a seal to prevent passage of fluids therebyand tightly engages the trocar or other surgical instrument. With thehub 38 abutting the housing 40, a skirt 136 extending distally from thefront wall 58 of hub 38 will be disposed within an open proximal end ofthe housing 40, and the detents 42 will hold the hub in position withrespect to the housing. In this position, the distal end 94 of theportal sleeve will be disposed substantially in alignment with theproximal edge of conical shoulder 50 of the trocar to facilitatepenetration by the trocar.

In use, it will be appreciated that with the pin 78 disposed in distaltransverse slot portion 86, the safety shield 34 cannot move proximallywithin portal sleeve 36 thereby assuring that the sharp tip 46 of thetrocar is protected to prevent inadvertent contact during handling anduse. When it is desired to penetrate an anatomical cavity, the bluntdistal end 64 of the safety shield is positioned in abutment with thetissue T to be penetrated as illustrated in FIG. 4, and a finger isutilized to manually move pin 78 counter-clockwise against the torsionalbias of spring 80 to be aligned with the longitudinal portion 84 of slot62. With the pin 78 in this position, when the distal end 64 of thesafety shield is forced against the tissue to be penetrated, the safetyshield 34 will move proximally against the bias of spring 80 to aretracted position as illustrated in FIG. 5. With the safety shield inthe retracted position, penetration through the tissue with minimaltissue jamming and trapping is accomplished due to the smooth profile ofthe distal end of the safety trocar penetrating instrument. Pin 78 willnot enter proximal transverse slot portion 88 when the pin is alignedtherewith due to the torsional or rotational bias of spring 80 in theopposite direction; and, thus, once the anatomical wall has beencompletely penetrated such that the force of tissue against the distalend of the safety probe is removed, spring 80 will bias the safetyshield distally such that the safety shield returns to the extendedposition as illustrated in FIG. 5 to protect the sharp tip 46 such thatthe sharp tip is exposed only during the tissue penetrating step. Oncethe safety shield has returned to the extended position, the pin 78automatically enters distal transverse slot portion 86 due to therotational bias of spring 80 to lock the safety shield in the extendedposition. If automatic locking of the safety shield 34 is not desired,the spring 80 is not wound during assembly such that pin 78 is notrotationally biased. Accordingly, after spring 80 returns the safetyshield 34 to the extended position when the force on the safety shielddistal end from tissue resistance is removed, the pin will not enterdistal transverse slot portion and the safety shield will not be lockedin the extended position. Thus, the surgeon has the option of lockingthe safety shield in the extended position by manually moving the pin 78into distal transverse slot portion 86 or allowing the safety shield tobe free to move proximally by not moving pin 78 into distal transverseslot portion 86.

If, after penetration into the anatomical cavity, it is desired topenetrate additional tissue, the surgeon can selectively release thesafety shield from the extended position by moving pin 78counter-clockwise to be aligned with longitudinal slot portion 84. Ifthe protection provided by the safety shield is not required or desiredfor further procedures, the pin 78 can be moved into recess 90 ofproximal transverse slot portion 88 to releasably lock the safety shieldin the retracted position or a position further withdrawn into portalsleeve 36 dependent upon the longitudinal position of proximaltransverse slot portion 88. Where proximal transverse slot portion 92extending in the same direction as the distal transverse slot portion,is provided, the safety shield will automatically lock in the retractedposition when pin 78 is aligned with proximal transverse slot portion 92due to the rotational bias from spring 80. If slot portion 92 ispositioned proximally of pin 78 when the safety shield is in theretracted position, the safety shield will not automatically lock duringuse but, rather, the pin will have to be manually pulled back toalignment with slot portion 92 to lock the safety shield in theretracted position.

While plate 76 rotates within Hub 38, safety shield 34 does not rotatetherewith to maintain alignment with trocar 32. Various indexconfigurations to maintain rotational alignment between the safetyshield and the trocar can be used, if desired; and, for example, thesafety shield can be splined with the trocar.

Once the trocar has been used to penetrate tissue to the extent desiredby the surgeon, the portal sleeve 36 can be left in place by withdrawingthe trocar unit from the portal unit; and, once the trocar unit iswithdrawn, valve assembly 112 will prevent fluid flow through the portalsleeve 36 and housing 40. If it is desired to then insert an instrumenthaving a diameter less than the diameter of trocar 32, adapter plug 124is removed from the proximal end of tube 122 and replaced with anadapter plug having a central aperture and tubular passage formed by theinner wall 130 of a diameter corresponding to, or less than, the smallerinstrument to be inserted.

For procedures where it is desired to gain access to an area of ananatomical cavity substantially offset from the longitudinal axis of thesafety trocar penetrating instrument, the portal sleeve can have anormal, non-linear configuration such that, once penetration iscompleted and the trocar unit is withdrawn from the portal unit, theportal sleeve will return to the non-linear configuration. For example,the portal sleeve is shown in dashed lines in FIG. 6 as having a curvedconfiguration 138 to which the portal sleeve returns when the trocar andsafety shield are withdrawn. Where the portal sleeve, the trocar and thesafety shield are made from a flexible material, the safety trocarpenetrating instrument can be employed in flexible endoscopy wherein,for example, the safety trocar penetrating instrument can be inserted inan operating channel of a flexible endoscope. Additionally, by formingthe portal sleeve, the trocar and the safety shield from a flexiblematerial, the safety trocar penetrating instrument can be insertedthrough non-linear anatomical passages.

In accordance with the present invention, the distal ends of the safetyshield and the trocar are specifically configured to cooperate to form asmooth profile minimizing resistance during tissue penetration. In theembodiment illustrated in FIGS. 1 and 4-6, the distal end 44 of thetrocar 32 has three, generally triangular, flat sides or facets 140tapering distally to sharp, tissue penetrating tip 46 from cylindricalneck 48. The junctions 142 of the flat sides 140 with the cylindricalneck 48 are curved to have a scalloped configuration, and thefrusto-conical shoulder 50 tapers distally from a circular junction 144with cylindrical trocar body 52 to a smaller circular Junction 146 withneck 48. The distal end 64 of the safety shield 34 is configured to matewith the distal end of the trocar when the safety shield is in theretracted position as best shown in FIG. 5. More particularly, thesafety shield distal end has a tapering conical wall 148 having an innersurface 149 disposed at the same angle relative to the longitudinal axisof the trocar as the angle of the outer surface of shoulder 50 relativeto the trocar longitudinal axis. Conical wall 148 joins cylindricalsafety shield body 150 proximally and distally terminates at acylindrical inner surface 152 having an axial length substantially equalto the axial length of trocar neck 48. The peripheral distal edge 154 ofthe safety shield is shown as being-circular, which is preferred if thetrocar tip is conical rather than faceted; however, distal edge 154 canbe scalloped or formed of curved segments 156, as shown in dashed linesin FIG. 4, corresponding in radius and arc of curvature to curvedjunctions 142 to provide exact mating of the safety shield and thetrocar in the retracted position. As shown in FIG. 5, when the safetyshield is in the retracted position, conical wall 148 is in contact withshoulder 50 along the length thereof while inner surface 152 is incontact with neck 48. Accordingly, the distal end of the safety trocarpenetrating instrument has a smooth profile presenting minimalresistance to tissue as a cavity wall is penetrated. More particularly,the angle of the outer surface of conical wall 148 is the same as theangle of the trocar tip relative to the trocar longitudinal axis suchthat wall 148 forms a smooth continuation of the trocar tip leading tothe distal end of portal sleeve 36. During penetration, the peripheraldistal edge 154 of the safety shield 34 initially engages the tissue andthen moves proximally as penetration continues until the safety shieldis in the retracted position shown in FIG. 5, it being noted that themating configurations of the safety shield and trocar distal endsproduces a positive stop to limit proximal movement of the safetyshield.

A modification of the safety shield distal end 64 is illustrated inFIGS. 7 and 8 at 158 with the primary difference being that, while theinner surface 159 of "conical" wall 148 has a configuration mating withneck 48 and shoulder 50 of the trocar tip, the outer surface of wall 148has flat sides or facets 160 having configurations to form extensions oftrocar tip facets 140 when the safety shield is in the retractedposition shown in FIG. 8. To this end, the number of safety shieldfacets 160 equals the number of trocar facets 140 and the angular orrotational orientation of the safety shield relative to the trocar issuch that junction lines or edges 162 between the trocar facets 140 arealigned with junction lines or edges 164 between the safety shieldfacets 160. The proximal end of each trocar facet 140 has a widthsubstantially equal to the width of the distal end of each safety shieldfacet 160 aligned therewith, and the safety shield facets 160 continueat the same angle to the trocar longitudinal axis as the trocar facets140 to terminate adjacent the distal peripheral edge 96 of portal sleeve36. The distal end of each safety shield facet 160 can be scalloped orformed of curved segments to conform in radius and arc of curvature tothe junctions 142 at a proximal end of each aligned trocar facet 140 toreduce gaps therebetween and further minimize tissue resistance duringpenetration. The trocar tip can have any number of facets arranged atregular or irregular positions; and, in accordance with the modificationof the present invention of FIGS. 7 and 8, the safety shield will have anumber of facets equal to and similarly arranged with the trocar facetsto produce a continuous smooth profile during penetration.

Another modification of the distal end of the safety trocar penetratinginstrument according to the present invention is illustrated in FIGS.9-12 wherein the trocar tip has a plurality of flat facets 166 asdescribed above; however, a depression in the form of a hole or recess168 is formed in a proximal portion of each facet, as shown in FIGS. 9and 11, and the facets 166 extend proximally to terminate adjacent thedistal peripheral edge 96 of the portal sleeve 36. The safety shield 34has a distal end 64 formed of a plurality of fingers 170 equal to thenumber of trocar facets 166, and each finger 170 is aligned with atrocar facet 166. The distal ends 172 of fingers 170 are rounded, andeach finger 170 carries a smoothly curved, inwardly protruding nub 174,as shown in FIG. 12, having a configuration to be received indepressions 168. Accordingly, when the safety shield is moved to theretracted position during penetration of tissue as shown in FIG. 10,nubs 174 will be received in depressions 168 such that the fingers 170form extensions of the trocar tip facets 166 providing a smooth profilepresenting minimal resistance to tissue when a cavity wall ispenetrated, and the hubs 174 received in the depressions 168 serve as apositive stop to limit proximal movement of the safety shield.

Another modification of the distal end of the safety trocar penetratinginstrument according to the present invention is illustrated in FIGS. 13and 14 wherein the trocar tip has a plurality of flat facets 166 asdescribed above extending proximally to terminate adjacent theperipheral distal edge 96 of the portal sleeve 36. The safety shield 34has a distal end 64 formed of a resilient, flexible material, preferablya rubber-like material such as silicone or latex, having a configurationto fit closely over the trocar tip. The safety shield distal end 64defines a plurality of legs 176 equal to the number of trocar facets 166with each leg 176 being aligned with a trocar facet 166. The legs 176have lateral edges 177 joined at radiused ends 178 aligned with thedistal peripheral edge 96 of the portal sleeve 36, as shown in FIG. 13,and tapering distally along the trocar facets 166 from the radiused ends178 to an apex. 180 forming a closed, blunt end disposed distally fromthe sharp trocar tip 46. In the extended position for the safety shield,the lateral edges 177 extend along the longitudinal axis of the trocar;and, when the safety shield is moved to the retracted position duringpenetration of tissue as shown in FIG. 14, the legs 176 will flex orspread outwardly from the longitudinal axis of the trocar and form asmooth profile with the trocar facilitating insertion in tissue of acavity wall. By forming the safety shield distal end of a resilientmaterial, the material itself can provide a bias for returning thesafety shield to the extended position upon removal of force from tissuecontact such that the structural arrangement at the proximal end of thesafety trocar penetrating instrument can be simplified. By selecting thematerial forming the safety shield distal end to provide a limiteddegree of outward expansion for the legs, a positive stop can beobtained limiting proximal movement of the safety shield.

Another modification of the distal end of the safety trocar penetratinginstrument according to the present invention is shown in FIGS. 15 and16 wherein the trocar tip tapers from the neck 48 to the sharp trocartip 46 to define a conical distal end, and a helical thread 180 extendsalong the conical trocar tip from the neck to the sharp tip. The safetyshield distal end 64 includes tapering conical wall 148 having an innersurface disposed at the same angle relative to the longitudinal axis ofthe trocar 32 as the angle of the outer surface of shoulder 50 relativeto the trocar longitudinal axis. Conical wall 148 joins cylindricalsafety shield body 150 proximally and distally terminates at cylindricalinner surface 152 having an axial length substantially equal to theaxial length of trocar neck 48. A helical thread 182 extends along thetapering conical wall 148 from cylindrical safety shield body 150 to acircular, peripheral distal edge 154 of the safety shield. Threads 180and 182 are like handed extending in the same angular direction with thelongitudinal axis of the trocar, and a proximal end of the thread 180merges with a distal end of the thread 182 when the safety shield is inthe retracted position shown in FIG. 16 with conical wall 148 in contactwith shoulder 50 along the length thereof while inner surface 152 is incontact with neck 48. Accordingly, the distal end of the safety trocarpenetrating instrument forms a smooth profile as well as a continuousthread extending along the trocar tip and the conical wall 148 of thesafety shield facilitating insertion of the distal end of the safetytrocar penetrating instrument in tissue forming a cavity wall. With theembodiment of FIGS. 15 and 16, the distal end of the safety trocarpenetrating instrument is inserted in tissue with a rotational motionproviding relatively slower penetration with greater control ofpenetration depth and is particularly advantageous for thoracic andbrain surgery.

The modification of FIGS. 16 and 17 can also be utilized for particularprocedures with no threads such that the conical tip cooperates with theconical wall of the safety shield to produce a smooth, continuousconical configuration during penetration. That is, when inner surface152 is moved proximally to contact neck 48, conical wall 148 will be anextension of the conical trocar tip.

Another modification of the distal end of the safety trocar penetratinginstrument is illustrated in FIGS. 17 and 18 wherein the trocar tip isthe same as that described for FIGS. 13 and 14, and the safety shielddistal end 64 is formed of a resilient, flexible, compressible andexpandable material that can fold or wrinkle, the material defining acurved wall 184 having a predetermined configuration in the extendedposition shown in FIG. 17. The curved wall 184 gradually tapers distallytoward the blunt, peripheral distal edge 154 of the safety shield 34disposed distally from the sharp tip 46 of the trocar 32. Duringpenetration of tissue of the cavity wall, safety shield 34 will becompressed proximally in the retracted position, as shown in FIG. 18,exposing the sharp trocar tip 46. By forming the curved wall 184 ofminimal thickness, a smooth profile is maintained with the trocar facets166 in the retracted position to minimize tissue resistance. By formingthe safety shield distal end of a resilient material, the materialitself can provide a bias for returning the safety shield to theextended position upon removal of force from tissue contact, and theamount of material compressed in the retracted position can act as apositive stop limiting proximal movement of the safety shield.

Another modification of the distal end of the safety trocar penetratinginstrument is illustrated in FIGS. 19 and 20 wherein the trocar tip isthe same as that shown in FIGS. 7 and 8, and the safety shield distalend 64 is formed of a resilient, flexible, compressible and expandablematerial configured to fit closely over the trocar tip and capable offolding or collapsing along fold lines 186 disposed concentrically withthe trocar tip. In the retracted position shown in FIG. 20, the safetyshield 34 is folded or collapsed along the fold lines 186 forming anaccordion-like configuration with annular ribs 188. The amount ofmaterial compressed or folded in the retracted position can be selectedsuch that the distal edge 154 of the safety shield is disposed adjacentjunction 142 in the retracted position with the ribs 188 defininggradually increasing diameters from the distal edge 154 to merge withthe distal peripheral edge 96 of the portal sleeve along the same angleas the trocar facets 140 with the trocar longitudinal axis to form asmooth profile facilitating penetration in tissue of a cavity wall. Byforming the safety shield distal end of a resilient material, thematerial itself can provide a bias for returning the safety shield tothe extended position upon removal of force from tissue contact, and theamount of material compressed in the retracted position can act as apositive stop limiting proximal movement of the safety shield.

A modification of a locking mechanism for the safety trocar penetratinginstrument of the present invention is shown in FIG. 22 wherein thetrocar unit including trocar 32, safety shield 34 and hub 38 isillustrated. The hub 38 is adapted to be coupled with housing 40 asdescribed in connection with FIG. 1 and includes front wall 58 havingopening 68 therein receiving the tubular body 66 of the safety shield34. Tubular body 66 terminates at proximal end 70 disposed within thehub and carrying an annular flange 190 which can be secured on proximalend 70 or formed as an integral part thereof. A slot 192 is formed intubular body 66 and extends longitudinally from flange 190 in a distaldirection in parallel alignment with the trocar longitudinal axis.Cylindrical body 52 of trocar 32 has an opening 196 formed thereinadjacent a proximal face of flange 190. Cylindrical body 52 terminatesat proximal end 54, and a lumen 197 is formed in cylindrical body 52.Proximal end 54 is secured in a central opening in an annular member 198releasably received, for example via a threaded connection, in an openproximal end 200 of hub 38. While the trocar body 52 and member 198 areshown as being made as one piece, the body 52 and member 198 can be madeas separate parts secured together in any desirable manner, such as bywelding, cement or threads for example. A positioning rod 199 has endssecured, respectively, to front wall 58 and member 198, the rod 199passing through an aperture in flange 190. A helical spring 202 isdisposed over rod 199 and is mounted in compression between member 198and flange 190 to bias the safety shield to the extended position withthe rod 199 preventing relative rotational movement of the safety shieldand trocar. Alternatively, spring 202 and rod 199 may be replaced with atelescoping-type spring having ends secured, respectively, to wall 58and member 198, or any other spring suitable for biasing the safetyshield to the extended position. An end cap 206 has a lip 208 extendingaround the periphery of member 198 such that the end cap can movelongitudinally, axially relative to hub 38. A hollow stem 210 extendscentrally from end cap 206 to be slidably received in proximal end 54 oftrocar 32, and a helical spring surrounds stem 210 and is mounted incompression between end cap 206 and member 198 to bias the end capproximally relative to the hub. A locking spring 212 illustrated in FIG.21 has a curved end 214 secured within trocar 32 and joined to a body216 bifurcated to form a proximally extending deactuating arm 218 and asubstantially transversely extending abutment arm 220, the abutment armpassing through opening 196 in trocar 32 and having a curved head 222terminating at a distally extending finger 224. A deactuator or releasearm 226 is mounted in stem 210 and has a protrusion 228 positioned toengage arm 220 of the locking spring.

In operation, the locking mechanism is normally in the condition shownin FIG. 22 with abutment arm 220 passing through opening 196 and finger224 disposed above cylindrical body 52 at a position to engage theproximal face of flange 190 such that the safety shield 34 cannot moveproximally and is, therefore, locked in the extended position protectingthe sharp tip of the trocar 32. When tissue of an anatomical cavity wallis to be penetrated, the hub 38 and the housing 40 are gripped in onehand with the palm of the hand engaging end cap 206; and, when the handis squeezed, end cap 206 is moved distally along hub 38 against the biasof spring 211 causing the protrusion 228 of deactuator 226 to movedeactuating arm 218 distally buckling the locking spring 212 and causingthe abutment arm 220 to move within the opening 196 in cylindrical body52 and out of the path of movement of flange 190 as shown in FIG. 23.Accordingly, the safety shield is now in an unlocked state and able tomove proximally from the extended position.

When the safety trocar penetrating instrument is forced into the tissue,the safety shield will move proximally against the force of spring 202and slide over the curved head 222 of the abutment arm of the lockingspring causing the locking spring to move further into the opening 196thereby freeing deactuating arm 218 from the protrusion 228 on thedeactuator 226 as shown in FIG. 24. Once the safety shield has moved tothe retracted position, the flange 190 will have passed proximallybeyond the opening 196 and out of engagement with abutment arm 220, andthe slot 192 will be vertically sligned with the opening 196 therebyallowing the abutment arm 220 to return to its normal position withdeactuating arm 218 overlapping protrusion 228 is shown in FIG. 25. Whenan anatomical cavity has been penetrated such that the force of tissueagainst the distal end of the safety shield is removed, the safetyshield will return to the extended position under the biasing force fromspring 202, camming over the curved head 222 of abutment arm 220 withthe abutment arm then returning to the locking position as shown in FIG.26. At this time, the end cap 206 remains in the compressed state fromgripping by the hand such that the deactuator 226 cannot release thelocking spring, and the safety shield automatically locks in theextended position. If it is desired to release the safety shield forfurther use of the trocar, the end cap must be released to return to theposition illustrated in FIG. 22 whereupon squeezing the end cap againwill release the safety shield for further penetration of tissue ifdesired.

Inasmuch as the present invention is subject to many variations,modifications and changes in detail, it is intended that the subjectmatter discussed above and shown in the accompanying drawings beinterpreted as illustrative and not in a limiting sense.

What is claimed is:
 1. A safety trocar penetrating instrumentcomprisingan elongate, tubular portal sleeve having a distal end and aproximal end; a housing coupled with said proximal end of said portalsleeve and having a valve therein for controlling fluid flow throughsaid housing and said portal sleeve and for allowing passage ofinstruments therethrough; a trocar disposed within said portal sleeveand having a longitudinal axis, a proximal end and a solid, distal endterminating at a sharp tip beyond said distal end of said portal sleevefor penetrating tissue; a safety shield disposed between said portalsleeve and said trocar and having a proximal end and a distal end andbeing movable between an extended position with said safety shielddistal end protruding distally of said trocar tip and a retractedposition with said safety shield distal end disposed proximally of saidtrocar tip to expose said trocar tip; a hub abutting said housing forreceiving said proximal ends of said trocar and said safety shield, saidtrocar and said safety shield passing through said a valve in saidhousing; bias means for biasing said safety shield toward said extendedposition and for permitting said safety shield to move proximally tosaid retracted position in response to a proximally directed forceapplied to said safety shield distal end, said bias means returning saidsafety shield to said extended position when the force applied to saidsafety shield distal end is removed; and stop means for limitingproximal movement of said safety shield wherein said trocar distal endincludes a plurality of angled, flat sides joined at edges and saidsafety shield distal end includes a plurality of legs equal to saidplurality of sides and having lateral edges aligned with said edges ofsaid sides and wherein said legs taper distally along said sides to anapex disposed distally of said tip in said extended position, said legsbeing formed of a resilient, flexible material allowing said legs toexpand outwardly from the trocar longitudinal axis in said retractedposition.
 2. A safety trocar penetrating instrument as recited in claim1 wherein said stop means includes a portion of said legs configured tolimit outward expansion of said legs in said retracted position.
 3. Asafety trocar penetrating instrument as recited in claim 2 wherein saidbias means is formed by a portion of said legs.